Seizures in Cats — Some of the Causes Might Surprise You
Most veterinarians will agree that seizures can be a terrifying event for cat families to witness and no wonder: The definition of a seizure is a sudden, abnormal and disorganized discharge of electrical impulses from brain cells. Just reading that description is frightening. Cats experiencing a seizure may abruptly and violently thrash about, chomp their teeth, drool, lose consciousness and often urinate or defecate. What causes these traumatic events and what can you do if one occurs? Let’s take a quick look at some of the reasons why cats can have a seizure.
Since a seizure is characterized as a disorganized activity of brain cells, it is not surprising that a variety of brain disorders, as well as a hemorrhage in the brain, can cause one. Severe head trauma can also set up a seizure “focus” in the brain. A “focus” occurs when brain cells don’t work quite right and seizures result. For example, my sister adopted a kitten that was abandoned at my hospital after he suffered head injuries when he was accidentally stepped on. He recovered from the acute injury (getting stepped on) but developed seizures shortly afterward. Seizures may also result when infections, like those caused by the fungus Cryptococcus, take root in the brain. Other diseases, such as feline infectious peritonitis, which can cause lesions in the brain, and brain tumors (something I, as a veterinary oncologist, frequently see), are also on the list of feline brain disorders associated with seizures.
Systemic or Environmental Causes
Sometimes, conditions outside the brain can affect its function and induce seizures. For example, untreated hypertension, most commonly from kidney disease, can result in seizures. The liver filters out many potentially seizure-causing compounds, such as dietary protein products that result after a typical meal. Young cats with a particular type of abnormal blood vessel that directs blood away from the liver (called a portosystemic shunt) can experience seizures because the shunt prevents these toxins from being filtered. Seizures can also result from exposure to toxins like antifreeze (ethylene glycol) or the application of flea and tick medications intended for use only on dogs and not cats. Accidental ingestion of certain human prescription medications, such as antidepressants and ADHD medications, can land many feline patients in the ICU with seizures.
Seizures from Sound?
Recently, researchers may have found another interesting possible cause of seizures in cats. In a recent issue of the Journal of Feline Medicine and Surgery, a group of British veterinarians reported on a new type of seizure syndrome termed “audiogenic reflex seizures” in which seizures are caused by a particular sound. In this study, seizures occurred in response to specific yet common everyday noises, such as the crinkling of aluminum foil, paper or plastic bags, the chinking of a metal spoon dropped into a food bowl and tapping on glass. Even the sound of ripping Velcro evoked a seizure in some cats! Cats suffering from these seizures were typically older (more than 15 years). Many of the owners were surprised that noises could induce seizures in their kitties since they believed their cats were deaf! The authors of the study speculated that the cats experiencing the audiogenic seizures still had an ability to hear sounds in the feline ultrasonic range, which meant the cats could still hear high-pitched sounds like crinkling and clinking. However, the “deaf” cats had lost the ability to hear human voices and lower pitched sounds, causing their owners to assume their cats were deaf.
It’s also important to keep in mind that not all conditions that look like a seizure in your cat are in fact seizures. Heart problems in cats can cause inadequate delivery of oxygen-rich blood to the brain, either because the heart muscle does not pump well or because of an abnormal heart rhythm. Lack of oxygen to the brain can cause your cat to faint. Sudden, yes; seizure no. Disorders of the muscles can result in weakness and collapse and veterinarians will also consider this diagnosis when evaluating a cat for possible seizures. Deficiency of the B vitamin thiamine can mimic a seizure because a lack of thiamine can cause dilated pupils, altered consciousness and a strange neck posture called ventroflexion, in which the head bows downward. Finally, if you have never experienced a female cat in heat, some owners might mistake her sudden yowling and flirtatious rolling as a seizure!
What Do You Do?
Here’s what I tell my clients. Your response to a seizure in your cat depends on exactly what happens when the seizure occurs: 1. If you observe what you think is a seizure but it stops after a minute and then your cat is relatively normal, you should see your veterinarian as soon as possible. 2. If you observe what you think is a seizure and it does not stop after a few minutes, or if multiple seizures occur in a cluster, you need to take your cat to the ER immediately. 3. Give your cat a wide berth during a seizure and don’t handle her any more than necessary or you could be seriously bitten or scratched. 4. If your cat needs to be transported to the ER, scoop her up in a thick towel to protect both of you during transport. If you need to go to the ER, a series of quick tests can help determine if low blood sugar or high blood pressure (for example) is causing the seizure. If necessary, intravenous medications will be administered to stop the seizure. Then, a more in-depth evaluation can be conducted to determine the cause of the seizure. Depending on the situation, a referral to a veterinary neurologist and possibly an MRI will be recommended. When an underlying cause of a seizure is identified, such as high blood pressure, then the cause can sometimes be treated. If no cause is identified, anticonvulsant medications may be prescribed to try to control the episodes. Even though seizures are frightening to watch in your most favorite feline fur person, controlling even chronic seizures while maintaining a very good quality of life is frequently possible. More on Vetstreet: